1. Field of Invention
This invention relates generally to a safety device for drivers and passengers of vehicles, such as automobiles, speedboats, aircrafts and the like, and is more particularly designed for preventing head or neck injury caused by sudden and dramatic change in speed, such as in traffic crashes.
2. Discussion of Related Arts
Although the use of safety belts has greatly reduced the number of injuries and deaths in traffic accidents, many drivers or passengers, generally referred to herein as “riders,” still suffer from head or neck injuries in traffic accidents or sudden and dramatic changes in speed when using safety belts. The deficiency of the safety belt is that it only restrains that portion of the body part below the neck of the seat-belt user. The head of the user is still subject to large deceleration forces during a crash, which often results in head or neck damage to the user, commonly known as “whiplash.”
Whiplash is a soft tissue (with or without bone) injury to the neck resulting in neck sprain or neck strain. Such injury is usually caused by the sudden backward movement (extension) and forward movement (flexion) of the neck during a vehicle crash when the rider's body experiences dramatic change in speed in a very short time interval. Severe whiplash may cause injury to intervertebral joints, discs, ligaments, cervical muscles and nerve roots, vertebral bone fracture, or may even be fatal to the rider.
During a crash or sudden change in speed, the head of the user is fixed safely on the headrest by the present invention, and the body part below the neck position of the user is fixed onto the seat by the seat belt. The continuing forward or backward movement of the head or the neck with respect to the body of the user is avoided by the present invention.
Prior art U.S. Pat. No. 6,363,540 discloses a helmet with the forehead portion of the helmet being connected to the seat by a strap. The disadvantage of this device is that during sudden deceleration, the restraint force is applied mainly to the forehead of the user, while the continuing forward motion of the head and neck, with the forehead being restrained, will result in hyper-extension, thereby causing neck injury. The strap also experiences high frictional force in the channel for its large contact surface area which hinders the turning movement of the user's head. The rigid shell design of the helmet is also inconvenient for a domestic car driver.
U.S. Pat. No. 4,909,459 discloses another restraint device. The disadvantage of this device is that a considerable length of the strap between the loop and the helmet is required to allow a free and smooth rotational movement of the user's head, while the increased length will fail to restrain the backward movement (extension) and forward movement (flexion) of the neck to prevent the whiplash.
Prior art U.S. Pat. No. 6,009,566 discloses another restraint device using a restraining yoke and collar. The disadvantage of this device is that it is inconvenient and uncomfortable for riders in domestic cars. The strap restrains the user's head movement in a horizontal plane and limits the rotational movement of the head. A considerable length of the strap is required to enable a free rotation of the user's head, while such increased length of the strap will reduce the protection against whiplash, as encountered in the '459 patent.
The existing safety restraints do not effectively restrain the backward movement (extension) and forward movement (flexion) of the neck so as to prevent whiplash. Some restraint devices are inconvenient and uncomfortable for the riders in domestic car. Other restraint devices either restrain the rotational movement of the user's head or otherwise limit the range of vision of the user.